21039687 has 12 divisors (see below), whose sum is σ = 31712304. Its totient is φ = 13416480.

The previous prime is 21039677. The next prime is 21039701. The reversal of 21039687 is 78693012.

It is not a de Polignac number, because 21039687 - 2⁴ = 21039671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21039647) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 50614 + ... + 51027.

It is an arithmetic number, because the mean of its divisors is an integer number (2642692).

Almost surely, 2^21039687 is an apocalyptic number.

21039687 is a deficient number, since it is larger than the sum of its proper divisors (10672617).

21039687 is a wasteful number, since it uses less digits than its factorization.

21039687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101670 (or 101667 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21039687 is about 4586.9038577236. The cubic root of 21039687 is about 276.0661073531.

The spelling of 21039687 in words is "twenty-one million, thirty-nine thousand, six hundred eighty-seven".